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Better Brakes & Steering for Our TJ Wrangler

Posted in How To: Suspension Brakes on August 12, 2019
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Disclaimer: Editor Hazel and Tech Editor Simons are longtime Jeep guys and warned us that this project would become far more involved than we anticipated. While we are pleased with the final product, it was hardly a bolt-on affair. We had to source parts from multiple vendors and do significant fabrication. If you just want stronger steering, there are bolt-on options that fit the bill. If you want to replace the inverted Y setup, there are even kits that do that, but they are expensive and you don't get larger brakes. It all comes down to your priorities.

The introduction of the TJ Wrangler in 1997 offered many advantages over the outgoing YJ, most notably the front and rear coil suspension. The subsequent Rubicon model that began in 2003 set the bar even higher with locking differentials and a 4:1 transfer case. What was sorely lacking, however, was adequate steering. The TJ uses an inverted Y steering configuration with a drag link that connects from the pitman arm to the passenger knuckle and a puny tie rod from the drag link to the driver knuckle. Furthermore, there's a bend in the passenger-side drag link to provide clearance when turning full-lock. And guess where the factory-style tubing always fails. You guessed it—at the bend.

Jeep used a separate drag link and tie rod on WJ Grand Cherokees though, and these vehicles are abundant in junkyards across the country. As an added benefit, WJs also use brakes with larger-diameter rotors and better calipers than TJs, a worthwhile upgrade when running big tires. While no one offers a complete kit for the WJ knuckle conversion, JKS Manufacturing does offer parts to complete this conversion, such as the knuckle flange spacer, axle-side track bar bracket, and track bar. JKS's Justin Mclean was instrumental in providing us with not only the right parts but also the information we needed in order to perform the conversion. The parts that JKS doesn't offer were sourced from Barnes 4WD, Skyjacker, WFO Concepts, and Powerstop. The parts combine to provide three benefits: stronger steering, shorter stopping distances, and improved suspension geometry.

The stock steering is adequate with factory-sized tires, but adding larger tires that are aired down for trail use would overtax the components. And that is before you turn on the front locking differential. Similarly, there is room for improvement in braking with larger, heavier rolling stock.

Starting with the steering, the original TJ tie rod is only 0.88 inch in diameter with a wall thickness less than 0.125 inch thick. We built a new tie rod and drag link from 1.5x0.250-wall DOM tubing and fitted it with QA1 threaded tube bungs we sourced from Summit Racing Equipment. These allowed us to run GM tie-rod ends we sourced from WFO Concepts that use a big 7/8-inch shank. While you can upgrade your TJ steering without adding WJ knuckles, another huge benefit is the better brakes. WJs use rotors that are a full inch larger in diameter, as well as being equipped with dual-piston calipers. While you can use the rotors, pads, and brake lines from the donor vehicle, we replaced the rotors and pads with new parts from Powerstop. The rotors do have to be redrilled from the WJ's 5-on-5 bolt pattern to 5-on-4 1/2, which is another reason to purchase new rotors if you are putting in this effort anyway.

While raising the drag link location reduces the change in angle as the suspension cycles, it won't do you any good if the track bar is not parallel to the drag link. JKS Manufacturing sells a bracket for the frame side to raise the track bar 4 inches to match the drag link. The other issue with the frame-side mount is that it uses a tie-rod end rather than a bushing. These tie-rod ends are weak, prone to wear, and limit the amount of suspension movement. We cut the factory bracket off the frame (no going back now!) and added a Barnes bracket on the outside of the frame that increased the length by 2 inches and converted the end to a bushing. JKS Manufacturing's DIY track bar spanned the distance between the two brackets, but by putting the bracket on the outside of the frame we ran into interference between the track bar bracket and factory sway bar. For now, we are running without a sway bar, but we plan to address that soon.

We started this project with a trip to the junkyard, where WJ Grand Cherokees are prevalent. Removal is fairly straightforward, although you do need a 12-point, 1/2-inch (or 13mm) socket for the unit bearings, a 36mm socket for the spindle nut, and a 27mm socket for the lower ball joint.

While we were swapping the knuckles, we also took the opportunity to replace our ball joints. This is not a requirement since the ball joint is fitted in the end forging on a Wrangler and not in the knuckle (as it is on, say, a Super Duty), but it is a good time to upgrade or replace your ball joints. We added Skyjacker's Rock Ready ball joints to our Dana 44 front axle. You probably think of Skyjacker as a suspension company, but it makes a host of other products, from brake lines to skidplates to, yes, ball joints. These ball joints are made in the USA and feature tapered roller bearings, are greasable, and use a powdered metal bearing instead of the factory plastic bearing. Yes, plastic! The Skyjacker ball joints all use an innovative design that distributes the load between the upper and lower ball joints for improved load carrying capacity, longer service life, and greater overall strength. We don't anticipate having to do any more for years to come than grease the ball joints.

After the conversion was completed, we were rewarded with a Jeep that worked significantly better on the street and on the trail. The improvement in braking is significant to the point where we had to adapt our braking habits or else we lock up the tires. The handling is much better as well, with geometry that is even better than the factory TJ offered. Cornering produces nearly no body roll, even with the sway bar disconnected. These were ancillary benefits in our search to upgrade our steering, but they end up being benefits that we appreciate every time we drive our Wrangler. While the installation was far from bolt-on, as the saying goes, "The juice was worth the squeeze."

The WJ uses 12-inch-diameter brake rotors, a full inch larger than the factory TJ rotors. All else being equal, larger rotors provide more stopping power as a result of the leverage they exert. Think of them like a breaker bar for bringing your Jeep to a halt.
One issue with using the WJ brake rotors is the bolt pattern. They use a 5-on-5 bolt pattern like a JK Wrangler, not the 5-on-4 1/2 of our TJ. The rotors register on the unit bearing, not the studs, so the bolt pattern doesn't have to be precise. Some people slot the 5-on-5 bolt pattern, but we had a machinist redrill our new Powerstop brake rotors.
The pad size is roughly equal between the two calipers, but the WJ calipers use twin pistons instead of one large piston for increased stopping power. Note that you want the later (2003-plus) Akebono calipers shown here, not the earlier (1999-2002) Teves calipers.
We had to flatten one side of our factory brake lines in order to fit properly with the new calipers. In retrospect we should have grabbed the WJ brake lines from the junkyard instead of cutting them. New WJ brake lines could also be used.
This is what we were after. Note how the WJ knuckle uses separate mounting points for the drag link and tie rod, and how much higher on the knuckle the drag link mounting point is.
We built a new tie rod and drag link out of 1.5x0.250-wall DOM tubing and fitted it with threaded bungs from QA1. We shouldn't have any issues bending these, even with heavy off-road abuse. If you use WJ tie-rod ends, JKS offers a drag link and tie rod for the conversion that do not require any welding, but you cannot use a tie-rod flip.
Some people have used the WJ tie-rod ends for their swap, as they are significantly larger than the factory TJ ones. They also have some strange bends in them, similar to JK tie-rod ends. We ended up using common GM tie-rod ends that we sourced through WFO Concepts.
We used a 7-degree-tapered reamer to modify the WJ knuckles and stock pitman arm to accept GM tie-rod ends. This should be done carefully a little bit at a time, because if you ream the knuckle too deep you will not be able to tighten the tie-rod end. We started with a hand drill but found that a drill press yielded much better results.
JKS make spacers that are required between the new WJ knuckle and the TJ unit bearing in order to provide the correct depth for the stub shaft. While laser-cut spacers sandwich between the two, JKS recommends welding them to the knuckle. We bolted the unit bearing to the knuckle prior to welding in order to avoid any warping.
You are likely familiar with the name Skyjacker when it comes to suspensions, but did you know that the company also offers such things as ball joints, skidplates, and brake lines? Swapping knuckles is the perfect time to install new ball joints, but rather than just replace we upgraded to Skyjacker's Rock Ready ball joints.
We could write an entire story about the Skyjacker ball joints. Instead of the lower ball joint carrying the entire weight of the vehicle, they distribute the load between the upper and lower ball joints for increased strength and longevity. Installation of these ball joints is slightly more complicated than traditional units, but the detailed instructions kept guesswork to a minimum.
The JKS track bar bracket at the axle end raises the track bar 4 inches to match the raised drag link location on the WJ knuckle. It also makes the track bar shorter though, in order to clear the coil spring. It is critical that the track bar and drag link are parallel in order to minimize bumpsteer as the suspension cycles.
The factory frame-side track bar bracket is a cast piece that is completed burned on to the frame. This stock mount uses a tie-rod end that is prone to wear and limits suspension travel. The Barnes frame side track bar bracket converts the end from a tie-rod end to a bushing, and it also sits outside of the frame to allow for the use of a longer track bar.
JKS has a variety of bolt-on track bars for TJs depending on lift height, but they also offer these DIY track bars that can be cut to length. They are available with either a bushing at the frame end or a Johnny Joint like we used.
This swap wasn't particularly quick or easy, but in the end we were rewarded with stronger steering, improved braking, and better handling on the street and the trail. Armed with this information your swap will hopefully go more smoothly than ours, whether you decide to make all, or just some, of these modifications.

 

Parts List
Here's the not-so-short rundown on what it takes to convert your 1984-2006 Jeep's Dana 30 to WJ knuckles for high steer.
WJ Grand Cherokee knuckles
WJ Grand Cherokee brake caliper brackets
WJ Grand Cherokee brake calipers (and hardware)
JKS WJ steering knuckle spacer, PN OGS930 x2
JKS Fab front track bar, PN OGS951
JKS Fab fab front track bar bracket, PN OGS920
Barnes frame side track bar bracket, PN B4W250149-1
QA1 RH tube adapter, PN 1844-132 x2
QA1 LH tube adapter, PN 1844-131 x2
GM RH tie-rod end, PN ES2010R
GM LH tie-rod end, PN ES2010L
Offset RH tie-rod end, PN EX23434R
Offset LH tie-rod end, PN EX23434L
Optional Parts
Skyjacker Rock Ready ball Joints, PN JD302B
Powerstop brake rotors, PN AR8742XPR
Powerstop Z36 brake pads, PN Z36-935

Sources

Barnes 4WD
828-551-7616
https://www.barnes4wd.com/
JKS Manufacturing
Coldwater, MI
517-278-1226
http://www.jksmfg.com
Power Stop
Torrance, CA
888-863-4415
http://www.powerstop.com/
QA1
Lakeville, MN
800-721-7761
http://www.qa1.net
Skyjacker Suspensions
West Monroe, LA
318-388-0816
http://www.skyjacker.com
Summit Racing
Akron, OH
800-230-3030
http://www.summitracing.com
WFO Concepts
Auburn, CA
530-268-9494
http://www.wfoconcepts.com

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